Electrically driven pencil sharpener



y 1951 H. R. DUCHESNEAU 2,561,438

ELECTRICALLY DRIVEN PENCIL SHARPENER Filed Feb. 23, 1949 3 wu wwto oHERVE R. ,DUGHESNEA U Patented July 24, 1951 UNITED STATES PATENT OFFICEELECTRICALLY DRIVEN PENCIL SHARPENER Herve R. Duchesneau, Hartford,Conn.

Application February 23, 1949, Serial No. 77,701

4 Claims. 1

This invention relates to improvements in electrically driven pencilsharpeners and more particularly to the switch means in the circuitsthereof and the mechanism for actuating said switches.

Electrically. driven pencil sharpeners hav been devised heretofore andhave included switch means in the motor circuit for energizing the motorupon a pencil being inserted within the sharpener. These switches havegenerally been of the type which are actuated by the side surface of a:pencil engaging a switch actuating member when the pencil is beingmoved into engagement with the cutters. Thus, the motor is energizedbefore the pencil actually engages the cutters. Further, and even moredisadvantageous, is the fact that the cutters will continue to cut awaythe pencil as long as it is held in engagement with the cutters,notwithstanding the fact that the pencil has already been sharpened asmuch as is possible by the sharpener.

Obviously, such characteristics of available sharpeners result in awaste of current by needlessly driving the motor with consequentneedless wearing of the machine, and an even greater waste occurs inexcessively cutting away useful lengths of pencils.

The objects of the present invention is to provide an electricallydriven pencil sharpener having a switch which is closed to energize themotor only when a pencil is thrust into engagement with the cutters ofthe sharpener whereby all actuation of the cutters will be effectivelyused to cut away the pencil while sharpening it.

A further object of the invention is to provide in the sharpener aswitch of the type which is automatically opened by an actuating memberengageable with the sharpened point of a pencil when the sharpening hasbeen completed in a predetermined manner, whereby only enough of thepencil is cut away to provide thereon a desired amount of sharpening,and further cutting of the pencil then automatically stops so as to notonly save current consumption but pencil lengths as well.

Details of these objects and of the invention, as well as other objectsthereof, are set forth in the following specification and illustrated inthe accompanying drawings forming a part thereof.

In the drawings,

Fig. 1 is a vertical sectional view taken on the line I-l of Fig. 2 andillustrating details 2 bodying the invention; particularly the means bywhich the switch is actuated.

Fig. 2 is a plan view of the pencil sharpener shown in Fig. l, the upperportion of the casing being removed in said view to illustrate detailsof construction.

Fig. 3 is a perspective view of a pencil sharpener embodying the presentinvention.

Thepencil sharpener embodying the principles of the present inventioncomprises a bi-partite casing, one part In of the casing enclosing themotor and gear box, while the other part I2 principally comprises a chipreceptacle in which an appreciable amount of chips and cuttings from thepencil, and bits of lead therefrom, may accumulate.

A wall I4 of the part II) of the casing is provided on one surface witha projecting boss I6 and the juxtaposed wall I8 of the part I2 of thecasing is provided with an aperture defined by an annular flange 20which is of suitable diameter to frictionally engage the outer surfaceof the boss I6 for purposes of holding part I2 of the casing removablysecured to part I0 thereof. Part I2 may thus be readily removed whennecessary for purposes of emptying therefrom the accumulations therein.

The surfaces of the wall It opposite that which is provided with boss I6has another boss 22 projecting therefrom, said boss being providedcentrally thereof with a cylindrical bearing 24 extending therethrough.

Said bearing 24 merges with another bearing portion 26 which is largerin diameter than bearing 24.. Adjacent bearing portion 26 and formedprincipally within boss I6 is a circular cavity 28 which merges with acavity30 of still greater diameter for purposes of receiving a ring gear32 which is fixed to the boss IB by any suitable means such as pressfitting the ring gear into the circular cavity 30.

Rotatably mounted within the adjoining bearings 24 and 26 is acylindrical shaft 34 to one end of which is secured a. frame 36. Saidframe'ineludes an'enlarged cylindrical portion 36 which is rotatablyreceived within bearing portion 26. The frame additionally comprises apreferably cylindrical portion 46 having a still larger diameter thanportion 38. Spaced from the portion 40 on the frame is a, pair of legs42 which extend in opposite directions from the central axis of theframe 36, and the end of the frame opposite the shaft 34 terminates in acylindrical sleeve 44 having an internal diameter sufficient to receivea lead pencil. Said sleeve 44 projects through an 3 opening 46 formed inthe outer wall of part l2 of the casing, said opening 48 being axiallyaligned with the opening in the opposite wall of part i2 which isdefined by flange 28.

Cylindrical portion 40 of the frame is provided with a plurality ofthreaded apertures 48 extending in from one side surface of the portion48 at a small angle to the axis of the shaft 34. The apertures 48 areequally spaced from the central axis of the shaft 34 and they alsoextend at equal angles to said axis. The legs 42 are also provided withcylindrical openings 58 which are equally spaced from the central axesof the shaft 3d and sleeve 54, The axes of said openings 58 are at equalangles to said central axis of the shaft 34 axes of the threadedapertures 48. V H

A plurality of cutter members 52 having helical cutting edges thereonare each provided at oneend with a spur gear 54. Said combined cuttermembers and gears are centrally apertured and positioned in the frame 36between the pairs of axially aligned threaded apertures 48 andcylindrical openings 58. A shaft. 56 extends through each of the alignedpairs of threaded apertures 58 and cylindrical openings 58, as well asthrough the central apertures of the cutter members 52 for purposes ofrotatably supporting the cutter members 52 at an angle to each other andat equal angles tothe axis of the shaft 34, as clearly shown in Fig. l.The innermost end of each shaft 56 is threaded for purposes of engagingthe threads of the apertures '18 to releasably lock the shafts 58 intheir operative positions. When the cutter members are mounted asdescribed, the spur gears 54 on them mesh with the teeth of the ringgear 32.

The free end of the shaft 84 projects beyond the outer end of the boss22 and securedthereto is a worm gear 58, said worm gear being providedwith a cylindrical socket 68 which receives said end of the shaft 34.Axially aligned with the socket to is an aperture 52 having an enlargedportion 64. The shaft 3% and frame 86, together with the cutter members52* carried thereby, are arranged to be movable as a unit a limitedamount axially relative to the boss 22. Engagement of the socketed endof the worm 58 with the outer end of the boss 22 limits the axialmovement of said shafted and frame 38 in one direction and theengagement of the innerend of the cylindrical portion of the frame withthe inner face of the cavity 28 limits the axial movement of the shaftand frame in the opposite direction.

As can be readily seen from Fig. 1, when the relatively movable partsare disposed the positions herein illustrated, there is a slight spacebetween the inner face of the cavity 28 and the inner end of thecylindrical portion 48 ofthe frame. The worm gear 58, as well as theshaft 3 3 and frame 36 connected thereto, are arranged to be rotatablydriven by a worm 68 fixed to one end of the armature shaft 6.8 of anelectric motor 18, which is secured in any suitable manner to the bottomof part 18 of the casing. In effect, the portion of the casing I 8 whichencloses the worm gear 58 and worm 68 comprises a gear box 12. The motorl8, as can be clearly seen from Fig. 2, is mounted within the remainingportion of part it of the casing from that comprising the gear box '12.v

ihe motor is connectible by a circuit compris ing a flexible cordconduit M to a source of current. For purposes of convenience, the motorIll.

should be preferably of the tym which. operates on conventionalhousehold current of 110 v., but the invention is not to be restrictedthereto. If

' desired, the motor may be of the type which can be driven fromelectric current supplied by a battery.

Connected in the circuit of the motor and conduit M is a switchgenerally designated 16. Said switch 56 is preferably of the typ Whichis responsive to Opening and closing movement of the order of a fewthousandths of an inch. While not restricted thereto, one type ofsuitable switch is sold under the name Micro and, in the exemplaryillustration on the several figures, comprises a pair of spring leafmembers 18 and 88 having contacts 82 at one end thereof. Said leaves 18and'88 are'insulated from each other and are connectible in saidcircuit. The switch is preferably enclosed within separablecasingmembers 84 and 86 and the switch may be secured to one wall of part 18of the casing by any suitable means such as screws 88.

The casing member 88 is provided with an aperture 88 through which aplunger 82 extends, said plunger preferably being provided with a headwhich is adapted to abut the inner surface of casing member 86 asclearly shown in Fig. 1. The, plunger 92 is also. centrally apertured toreceive another plunger 94, the latter being positioned to engage leaf'18 of the switch; plunger 92 being positioned to engage leaf thereof.Leaf 88 is also provided with an aperture 98 through which plunger 94extends.

Projecting perpendicularly outward from the outer face of worm gear 58is a thrust member 88 which is centrally apertured and headed at itsinner end, said end abutting the free end of the shaft 34, as shown inFig. 1. The head of said thrust member 88 is accommodated within theenlarged portion 64, of the aperture 82 within the worm gear 58. Thus,said headed member and enlarged portion maintain the thrust memberconnected to assembled worm gear 58 and shaft 34, whereby the thrustmemher is rotatable as a unit therewith when the motor 18 is. energized.The outer end of the thrust member 98 engages the outer end of theplunger 92 and, when the shaft 34 is positioned within the boss 22 asshown in Fig. 1, the switch contacts 82 are separated and the motor isdeenergized.

When a pencil is inserted within the sleeve 44 and the tip thereofengages cutter members 52', the thrust force imposed by the pencil uponthe cutters, and consequently upon the frame 86 and shaft 34, serves tomove the shaft and frame axially of the shaft a short distance,amounting preferably to between .005 inch and .010- inch, toward theleft as viewed in Fig. 1. Such movement of the shaft 34' and frame38 islimted, for example, by the engagement of the inner end of cylindricalportion 48. of the frame withthe inner face of cavity 28*. Correspondingmotion is imparted to the thrust member 98 and plunger 92 with resultingmovement of the leaf 8!) which causes the contact 82 thereon to engagethe other contact 82. circuit and and the motor will be energized todrive the worm 6t and worm gear 58 for purposes of rotating the shaft 34and frame 36..

Such rotation causes the cutter members 52 to be rotated about theirshafts 56 due tothe engagement of the gears 54 thereon with thestationary ring gear 32. Said cutters will also be rotated about theaxes of shaft 34- and frame 36 As. long as contacts 82 remain in engage-Such engagement closes the ment, the motor will continueto rotatethegcut ters for purposes of sharpening a pencil: Chips and shavingsfrom the pencil will readily drop from the cutters into the part l2 ofthe casing which comprises an ample receptacle for the same. l

, The thrust member 98 and shaft 34 are each provided with a smallaperture extending throughout the length of each end in axial alignmentwith each other for purposes of accommodating a long, needle-likeactuator I00 which projects at one end slightly between thegears 54 and,at the other end, engages the end of plunger 54 which is disposed withinthe aperture of the plunger 92. Said actuator is preferably of smalldiameter so that it is relatively light in weight.

After the pencil I 02 has been sharpened a predetermined amount and thepointed lead tip I04 thereof projects a predetermined amount inward fromthe sleeve 44, said pointed tip will engage the end of the actuator Hillwhich is ad-: jacent gears 54 and thrust saidactuator a very shortdistance axially toward the left asviewed in Fig. 1 so as to moveplunger 94 and leaf 18 toward the left to cause the contacts 82 of theswitch to separate by moving leaf 18 away from leaf 88. Such movement ofthe actuator I00 need only be of the order approximately .005 inch andsuch separation of the contacts will cause the motor to stop.

When the motor stops, the same will serve as asignal that the pencil hasbeen sharpened the desired predetermined amount and the pencil is thenquickly removed from the sharpener. When the righthand end of theactuator Inn is disengaged by the sharpened tip of the penciljthe leaf18 of the switch will bias the plunger and actuator toward the right asviewed in Fig. 1, since bythat time, the pencil I82 will also havedisengaged the cutter members 52 and the frame 36 and shaft 34 arelikewise moved toward the right in Fig. 1 due to the biasing force ofany suitable means such as a helical spring I08 which is mounted withinthe part of the hearing portion 28 between opposing faces of saidbearing portions and cylindrical portion 38 of the shaft 34. Suchmovement will cause thrust member 98 to momentarily disengage thejuxtaposed end of plunger 92. Since the latter is of lightweightmaterial such as any suitable fiber or synthetic resin, the leaf 8!] ofthe switch is capable of moving said plunger 92 toward the right inFig. 1. Thus, the contacts 82 of the switch will be again disposed intheir normal, spaced relationship as illustrated in Fig. 1.

In view of the foregoing, it will be seen that not only are simple anddurable means provided for utilizing the thrust force of a pencil forclosing the switch of the circuit described above for purposes ofenergizing the motor to cause rotation of the cutter to sharpen apencil, but simple and effective means are additionally provided forcausing the switch to be opened after the pencil has been sharpened adesired predetermined amount, whereby the motor will then be stoppedwith a resulting saving in current and lengths of pencil. This has notbeen possible when using electrically driven pencil sharpeners presentlyavailable.

Further, the components of the present invention are relatively few innumber, simple and inexpensive to manufacture, and are capable of beingeasily assembled. Also, the cover portion of the part ID of the casingwhich encloses the motor and gear box ma be'quickly removedto completely,expose'the operating mechanism of the pencil sharpener in the eventrepairs or adjustments are required.

It will be understood that adjustments may be made in the distances thethrust member 98 and actuator I move so that the contacts 82 of theswitch may be closed quickly immediately following the insertion of thepencil tip between the cutter members 52, and also so that the contactsmay be quickly and effectivel separated at the completion of sharpeningof the pencil for purposes of stopping the motor. The exemplary amountsof movement described in detail hereinabove are merely to be comideredillustrative and not restrictive.

While the invention has been illustrated and described in its preferredembodiment and has included certain details, it should be understoodthat the invention is not to be limited to the precise details hereinillustrated and described since the same may be carried out in otherways, falling within the scope of the invention as claimed.

What I claim as my invention is:

1. An electrically driven pencil sharpener including an electric motor,a frame having at one end a shaft mounted for rotation and limitedlongitudinal movement, cutter means rotatably supported by said frame,drive means interconnecting said cutter means and motor and by whichsaid frame is rotated and said cutter means actuated to sharpen a pencilwhen said motor is energized, and a circuit by which said motor isconnectible to a source of current; in combination with switch meanshaving relatively movable contacts and a plunger movable to close saidcontacts, said switch being mounted adjacent one end. of said shaft andthe plunger of said switch being engageable by said end of said shaftwhen a pencil is thrust against the cutter means supported by said frameto' close said switch and energize said motor to cause said pencil to besharpened by said cutter means, and an actuator movable relative to saidframe and engageable at one end with said switch, the other end of saidactuator being arranged to be engaged by the sharpened tip of a pencilat the completion of the sharpening thereof and moved by said sharpenedtip to open said switch and stop said motor.

2. An electrically driven pencil sharpener including an electric motor,a frame having at one end a shaft mounted for rotation and limitedlongitudinal movement, cutter means rotatably supported b said frame,drive means interconnecting said cutter means and motor and by whichsaid frame is rotated and said cutter means actuated to sharpen a pencilwhen said motor is energized, and a circuit by which said motor isconnectible to a source of current; in combination with switch meanshaving relatively movable contacts and a plunger movable to close saidcontacts, said switch being mounted adjacent one end of said shaft andthe plunger of said switch being engageable by said end of said shaftwhen a pencil is thrust against the cutter means supported by said frameto close said switch and energize said motor to cause said pencil to besharpened by said cutter means, and an actuator extending longitudinallythrough said shaft and plunger and movable longitudinally relativethereto, said actuator being engageable at one end with said switch andthe other end being arranged to be engaged by the sharpened tip of apencil at the completion of the sharpening thereof and moved by saidsharpened tip to sepa rate the'contacts of and thereby open said switchand stop said motor. r

3. An electrically driven pencil sharpener including anelectric motor, aframe having at one end a shaft mounted for rotation and limitedlongitudinal movement, cutter means rotatably supported by said frame,drive means interconnecting said cutter means and motor and by whichsaid frame is rotated and said cutter means actuated to sharpen a pencilwhen said motor is energized, and a circuit by which said motor isconnectible to a source of current; in combination with switchmeanshaving relatively movable fingers carrying contacts, a plungerassociated with said switch and movable against one switch finger toclose said contacts, said switch being mounted adjacent one end of saidshaft and said plunger being engageable by said endof said shaft when apencil is thrust against the cutter means to close the contacts of saidswitch and energize said motor to cause said pencil to be sharpened bysaid cutter means, and a needlelike actuator extending longitudinallthrough said shaft and plunger and movable longitudinally relativethereto, said actuator being engageable at one end with the other switchfinger and the other end thereof being engageable by the sharpened tipof a pencil at the completion of the sharpening thereof and movable bysaid sharpenedtip against said other switch finger to open said switchand stop said motor.

4- An electrically driven pencil sharpener ineluding an electric motor,a frame having at one end a shaft mounted for rotation and limitedlongitudinal movement, cutter means rotatably supported by said frame,and a circuit by which said motor is connectible to a source of current;in combination with means supporting said frame, a worm driven by saidmotor, a worm gear 8 fixed" to said frame and 'engage'able" wan-saidworm, the axes of said worm and worm gear being substantially at a rightangle to each other so as to permit limited movement of said gearrelative to said worm in a directiontransverse to the axis of said worm,a switch havingrelatively movable contacts and mounted adjacentoneend'of said shaft, a plunger movable rela tive to said switch andinterengageable with'one of said contacts, said plunger being engageablewith said one end of said shaft when a pencil is thrust against thecutter means supported by said frame to move said one contact intoengagement with said other contact and close-- said switch to energizesaid motor and cause said pencil to be sharpened by said cutter means,means on said frame engageable with fixedmeans on said support means tolimit longitudinal movement' of said one end of said shaft andplunger,and' an actuator movable longitudinally of said frame and:interengageable at one end withthe other switch contact, the other endof said actuator being arranged to be engaged by the sharpened tip of apencil at the completion of the sharpening thereof and be moved bysaidisharpened tip toseparate said contactsof and open said switch tostop said motor.

HERVE R. DUCHESNEAU.

REFERENCES cI'rED The following references are of record the file ofthis patent: a

